As is well known, bearings enable relative movement between two or more components. A variety of different bearing types are known and utilized on a regular basis. Some types of bearings, such as so-called “thrust bearings” and certain embodiments of radial bearings, conventionally include bearing surfaces that at least partially contact and move or slide relative to one another. These bearing surfaces are prone to wear due to their interaction with one another and, as such, are formed from appropriate wear-resistant materials. For example, such bearing surfaces may include a superhard material for resisting wear during use of the bearing. In one particular example, at least one or both of the bearing surfaces may be formed of a material comprising diamond (e.g., polycrystalline diamond).
As noted above, bearings may be used in numerous applications. In one example, bearings used regularly in subterranean drilling equipment. Such equipment may include drilling motors and drill bits having multiple components that move relative to one another and may be utilized for drilling boreholes into a subterranean formation, such as for oil or gas exploration. In a conventional downhole drilling motor, the motor is suspended at the lower end of a string of drill pipe that includes a series of pipe sections connected together at joints and supported from the surface. A rotary drill bit (e.g., a fixed cutter drill bit, roller cone drill bit, a reamer, etc.) may be supported below the drilling motor (via pipe sections, drill collars, or other structural members as known in the art) or may be directly connected to the downhole motor, if desired. Drilling fluid, often referred to as drilling mud, is circulated through the pipe string and the motor to generate torque within the motor and to cause the rotary drill bit to rotate. Bearings are conventionally used to enable efficient relative rotation of the rotary bit and other components of the drill string.
Many types of bearings may be used in such a drill string assembly, including bearings that may be employed by a rotary drill bit. One particular example includes radial bearings. In one embodiment, an inner and outer race are each provided with a plurality of bearing elements. The races are positioned adjacent one another so that the bearing surfaces of the bearing elements contact one another. As may be appreciated, geometry and configuration of the bearing elements of the races may be an important factor influencing the performance and life of such bearing structures. Some examples of conventional radial bearing apparatuses are disclosed by U.S. Pat. Nos. 4,662,348, 4,729,440, 4,738,322, 4,756,631, 4,764,036, 4,802,539 and 5,364,192 the disclosures of each of which are incorporated, in their entireties, by this reference.
It is a continued desire within the industry to provide improved bearing elements and apparatuses including such elements.